Custodians:

David Sinclair (CIMCO Ontario head) on refrigeration

(phone call with Jutta Mason, Dec.20, 2018)

Q: I guess CIMCO built and maintains most of the City of Toronto's outdoor rinks. Is CIMCO one of the biggest rink-building companies anywhere?

A: We used to be mainly based in Canada, but after Donald Trump told our story in his memoir, our business increased a lot in the U.S. and elsewhere. He hired us in 1986 (when he was still a businessman, long before he became President) to rebuild the rink in Central Park, and when we came in early and under budget, he let everybody know about it. The Globe did a story about it in 2017.

[Ed.note: Much earlier -- in 1986 when the new rink was opened -- the NY Times analyzed why it's so hard for city governments to build its projects the way the Central Park rink was built.]

Q: Is ammonia refrigeration more dangerous than other methods?

A: Refrigeration always involves heavy machinery and some kind of coolant, such as freon, ammonia, or CO2. Every kind of refrigeration plant will need to be operated competently. No cooling agent is without risk. Freon is damaging to the atmosphere. An ammonia leak is dangerous in the high concentrations needed for refrigeration plants. On the other hand, you can smell an ammonia leak. In a CO2 plant, if there was a major leak and a room began to be filled with CO2, the workers couldn't smell it and might die.

People worry about ammonia danger and I ask them: how do you heat your house? Oh, with natural gas? How do you sleep at night?

Because natural gas is explosive, and you sleep on top of pipes filled with it. But it doesn't stop us from using that as a very common way to heat our houses. The important thing is to take proper care of any system that we set up.

[Ed. Note: I looked up ammonia online after speaking to Mr.Sinclair, I got this from a safety company's website:]

According to the International Institute of Ammonia Refrigeration (IIAR), ammonia is 3 to 10% more thermodynamically efficient than competitive refrigerants. This allows an ammonia-based refrigeration system to achieve the same cooling effect while using less power. As a result, where ammonia refrigeration is appropriate, it can offer lower long-term operation costs.

Ammonia breaks down in the environment very quickly (lasting less than a week in the air). Unlike synthetic refrigerants like CFCs, it doesnít damage the ozone layer. Most of ammoniaís potential for harm relies on there being too much of it in one place, not on its being leaked and scattered into the environment. In fact, ammonia is often sprayed on fields as a fertilizer in industrial farming.

Finally, most people will notice the pungent smell of ammonia when itís only about 20 parts per million (ppm) in the air. While some refrigerants have no noticeable smell, allowing small leaks to go unnoticed, thatís not the case with ammonia. Even a tiny amount in the air will be obvious. Importantly, the detectable concentration is much lower than the concentration that will cause immediate harm.

Q: What about energy use? For example, replacing all this refrigeration machinery every 25 years with new machinery seems pretty wasteful. And replacing the concrete of a rink slab takes an enormous amount of energy, concrete is one of the big factors in global warming concerns.

A: In regard to the machinery, some rink plants can last for 35 years. But after 25 years, your chances of a problem can be unacceptably high. So a lot of municipalities prefer not to take the chance. Once there's a serious break-down, a rink can be out for a whole season, and the community won't be happy.

I can tell you a story about a time when a chiller had a problem in Mississauga in 2015, and we had to work really hard to fix it so the rink wouldn't be out for a season. Hazel McCallion was still mayor then, and she was so appreciative that she held a luncheon afterwards for the CIMCO team of mechanics who had managed to fix the problem in three weeks.

Q: When rink compressors work all the time in high-sun March, do they wear out sooner, because the machinery has to work so hard?

A: You can't overwork the machinery. It's built to run all the time if it has to. But if the sun is too high, the ice will be bad. When the rinks are kept running despite late-season warm weather, it doesn't harm the plant but the slushy ice is not popular with rink users.

Q: Is a CO2 rink better than one that uses ammonia?

A: Each cooling method has its advantages and disadvantages. There's a new kind of rink refrigeration called Transcritical CO2, which has been installed at the new skating trail at College Park. That kind of system is very economical in energy-use under normal winter conditions. If it gets too warm out, though, the ice quality is not as good.